uniform float speed;
uniform vec4 color;
vec2 center = vec2(0.5,0.5);

czm_material czm_getMaterial(czm_materialInput materialInput){
  czm_material material = czm_getDefaultMaterial(materialInput);
  vec2 v_st = materialInput.st; // 获取uv坐标
  
  float iTime = fract(czm_frameNumber * speed / 1000.0);
  float invAr = 1.0;

  vec2 uv = v_st;
    
  vec3 col = vec4(color.rg + uv, color.b + 0.5+0.5 ,1.0).xyz;
  
  vec3 texcol;
      
  float x = (center.x-uv.x);
  float y = (center.y-uv.y) *invAr;
    
  //float r = -sqrt(x*x + y*y); //uncoment this line to symmetric ripples
  float r = -(x*x + y*y);
  float z = 1.0 + 0.5*sin((r+iTime*speed)/0.013);
  
  texcol.x = z;
  texcol.y = z;
  texcol.z = z;
  // float d = abs(1.0 / (s * 10.8)) - 0.01;
  // fragColor = vec4(col*texcol,1.0);
  material.alpha = pow(z , .1);
  material.diffuse = col*texcol.rgb * z;
  return material;
}